Who is gwendolyn in the fairy tales?

If I am not mistaken she is the ( Miracle Hen) or Goose that lays the golden eggs. I seem to recall kiddy books with the title- Gwendolyn, the miracle hen, which pretty well tells the whole tale- like ( in a totally different vein) ( I was a Communist for the F.B.I.) which sums up the plot idea in a title ( many do not- many films have misleading titles, as do books- and there is a popular adage about this.